1. Field of the Invention
This invention relates generally to editing data converting apparatus, and more particularly to an editing data converting system for use with an editing apparatus for a cinema film in which a cinema signal of the cinema film is converted to a standard television signal and recorded on a magnetic tape and the cinema film is edited on the basis of an editing of the magnetic tape.
2. Description of the Prior Art
Recently, an editing apparatus for editing a video tape has been rapidly developed and various kinds of automatic editing apparatus are now available on the market, in which an editing point or location is specified by an address signal and editing data stored in a computer is used whereby the dubbing of the video tape is carried out by batch processing. Since such video tape editing apparatus can increase the accuracy of editing and can easily change the editing location and so on, the video tape editing apparatus becomes useful for editing cinema film. In editing the cinema film by using such video tape editing apparatus, a video tape for editing or a so-called work tape on which a cinema signal of the cinema film is recorded is edited by using the above-described video tape editing apparatus and on the basis of the editing data thus obtained, the original cinema film is cut and then connected.
An example of a prior art video signal editing system will be described with reference to FIG. 1.
FIG. 1 is a schematic diagram showing an example of a cinema film editing process which is carried out by using a prior art video tape editing apparatus. In FIG. 1, the picture image of an original cinema film 1 is converted to a standard television signal of, for example, an NTSC (national television standard committee) system by a so-called telecine apparatus 2 which comprises a television projector and an image pick-up device. This standard television signal from the telecine apparatus 2 is supplied to a video tape recorder (VTR) 3 for use in making a work video tape and then recorded on an off-line cassette type video tape or work video tape 4. In this case, since an absolute address of a frame of the cinema film 1 representated by the precise "hour, minute, second" and an absolute address of a frame of a cassette video tape 4 similarly representated by the precise "hour, minute, second" are normally different from each other, data of a corresponding relation therebetween including a reference cinema frame address and a reference video frame address thereof is supplied to the editing apparatus before starting the editing. Such work cassette video tape 4 is loaded onto a pluraltiy of editing VTRs 5.sub.1, 5.sub.2 and 5.sub.3. Reference numerals 6 and 7 respectively designate a control/memory section and an operation keyboard pad or table, and the control/memory section 6 is connected through interfaces provided therein to the editing VTRs 5.sub.1, 5.sub.2 and 5.sub.3. Various editing operations are carried out by using a full keyboard, a function key, a ten key and so on of the operation keyboard pad 7. Reference numeral 8 designates a display section of the editing apparatus and reference numeral 9 designates a picture image monitor. The states of the VTRs 5.sub.1, 5.sub.2 and 5.sub.3, an editing information or data and so on are displayed on the display section 8. After the editing is ended, an editing list 10 of 24-frame film mode is printed out from the control/memory section 6. Then, in accordance with this editing list 10, the cinema film editing is carried out by a cinema film editing apparatus 11 and thus an edited film 12 is obtained therefrom.
As is known well, a standard speed of a cinema film is 24 frame/second and a standard speed of a television video tape of the standard NTSC system adopted in Japan is 30 frame/second (=60 field/second). Thus, the number of the picture images of the cinema film and that of the picture images of the television video tape are different from each other per unit time and at every period of 1/12 second, 2 frames of the cinema film are corresponding to 5 fields of the television video signal.
For this reason, in the television projector, the cinema film is not pulled-down (shifted) at every 1/24 second in an equal interval but in the period of 1/12 second, a frame at an odd address of the cinema film is transmitted at every 1/30 second and a frame at an even address of the cinema film is transmitted at every 1/20 second, so that successive frames of the cinema film are made to correspond respectively to 2 fields and 3 fields of the television video signal. This operation is repeated to thereby pull-down the cinema film at 24 frames per second. Such pull-dwon system is called a 3/2 pull-down system and is now widely used.
FIG. 2 schematically illustrates the concept of the above-described 3/2 pull-down system. In FIG. 2, letters F and V respectively designate one unit length of a cinema film, namely, 4 frames (relative addresses F.sub.0 to F.sub.3) of the cinema film and one unit length of the television video signal (video tape), namely, 5 frames (relative video addresses V.sub.0 to V.sub.4) of the video tape. In FIG. 2, reference letter Pd designates a film of the 3/2 pull-down system.
As will be clear from FIG. 2, a first field and a second field of each of the frames V.sub.1 and V.sub.2 at first and second addresses of the video tape respectively correspond to picture images of two adjacent frames (for example, F.sub.0, F.sub.1 and F.sub.1, F.sub.2) of the cinema film. In the general video tape editing apparatus, since the resolution of the address signal, for example, the longitudinal time code of, for example, SMPTE (society of motion picture and television engineers) is determined by a frame unit, if either of the above-mentioned first and second frames V.sub.1 and V.sub.2 is designated as an editing point, it is not possible to specify the frame address of the cinema film immediately.
In the prior art, without considering the existence of the frames of the video tape such as the above-described V.sub.1 and V.sub.2 which bridge two frames of the cinema film, the editing data of the video tape is properly converted to the editing data of the cinema film. Thus, there is then a defect that the editing becomes inevitably low in accuracy.
Furthermore, if field information or data is added to the address signal and then the editing of the video tape is carried out, film editing data of high accuracy is obtained from the video tape editing data. To this end, however, since the existing video tape editing apparatus and VTR must be modified extensively, the manufacturing cost of the editing apparatus and VTR is increased and this is not economical. In addition, if by using the existing video tape editing list of 30 frames as an intermediate medium, the film editing list for 24 frames of the cinema film is printed out, the field data is dropped out.